Hi all,
Im just starting to get back into flat water sailing and I've been dusting off some very old kit so my wife and I can sail flat water during winter.

We have a old fibreglass era, speed/slalom board that has approximately a (0.5mm depth) negative hollow in its rocker line.

Its located in the centre stringer area in front of the fin box and is about 300mm long.

Was this some old design thing from the 80's ? or 90's. ?
Or
Is negative rocker a speed thing ?

It's difficult to photograph but I've tried to show what I mean in the pics, with the camera pointing forward from the fin box towards the front of the board, I have used a aluminium straight edge and some paper to try and show the gap clearance.




PS The Aussie guy that shaped this board, who I believe is still around today.